1. Field of the Invention
The present invention relates to a laser video projector for projecting an image to a plurality of screens, and more particularly, to a laser video projector using laser as a light source for modulating light from the light source by an acousto-optic modulator (AOM) according to a video signal and projecting video information to a plurality of screens using a scanner.
2. Description of the Related Art
A flat panel display device such as a liquid crystal display or a cathode ray tube of a television set is a conventional representative video display means. However, the cathode ray tube or the liquid crystal display is more difficult to manufacture and the resolution becomes worse as the screen size increases. Accordingly, there are limits to the practical use of the cathode ray tube or the liquid crystal display the screen size of which becomes larger. Therefore, a method of enlarging an image displayed on the cathode ray tube or the liquid crystal display by a lens and projecting the enlarged image to a screen is used in order to realize a large screen.
A method of projecting red, green, and blue images to the screen one above the other using three cathode ray tubes and three lenses independently is disclosed in U.S. Pat. No. 4,942,525 and a method of composing images having the respective colors from the three cathode ray tubes and projecting the composed image to the screen by a lens is disclosed in U.S. Pat. No. 4,842,394.
The conventional video displaying method in the cathode ray tube or the liquid crystal display, used for displaying an image on a large screen has problems in that the picture projected to the screen is not clear since the displayed image is projected after being enlarged by the lens only and that the brightness is low since the output of the light source is limited since the video displaying means, in particular, an optical system can be damaged due to a temperature characteristic.
Also, in the conventional video projector such as the cathode ray tube or the liquid crystal display, an image is projected to a screen by a projector. Considering that the demand for outdoor advertisements using a large screens is remarkably increasing, the fact that it is not possible to display an image on a plurality of screens from a video projector may deteriorate the effect of advertisement. Furthermore, when the image is projected after being enlarged by the lens only, the picture quality worsens when the image is projected to a plurality of screens.